Method of transferring micro devices

1. A method of transferring micro devices, comprising: providing a carrier substrate, on which a buffer layer and a plurality of micro devices are disposed, the buffer layer being located between the carrier substrate and the micro devices, an upper surface of each of the micro devices is entirely in contact with the buffer layer, the micro devices being separated from one another and positioned on the carrier substrate through the buffer layer; providing a bonding layer between the micro devices and a receiving substrate; making a receiving substrate contact the micro devices on the carrier substrate; after the micro devices contact the receiving substrate, reducing bonding force between at least a portion of the micro devices and the carrier substrate by melting the buffer layer through raising a temperature of the carrier substrate; and liquefying the bonding layer by raising a temperature of the receiving substrate such that adhesive force between the at least a portion of the micro devices and the bonding layer is greater than bonding force between the at least a portion of the micro devices and the carrier substrate, so that the at least a portion of the micro devices are released from the carrier substrate and transferred onto the receiving substrate, wherein a number of the at least a portion of the micro devices is in a range from 1000 to 2000000.

2. The method of transferring micro devices as recited in claim 1 , wherein the buffer layer covers a lower surface of the carrier substrate and the micro devices expose a portion of the buffer layer.

3. The method of transferring micro devices as recited in claim 1 , wherein the buffer layer comprises a plurality of buffer parts corresponding to the micro devices, and the buffer parts are separated from one another and expose a portion of the carrier substrate.

4. The method of transferring micro devices as recited in claim 1 , wherein making the receiving substrate contact the micro devices on the carrier substrate comprises: providing a bonding layer between the micro devices and the receiving substrate, the micro devices contacting the receiving substrate through the bonding layer.

5. The method of transferring micro devices as recited in claim 4 , wherein the bonding layer is formed on the micro devices or on the receiving substrate so as to entirely cover a plurality of lower surfaces of the micro devices or an upper surface of the receiving substrate.

6. The method of transferring micro devices as recited in claim 4 , wherein the bonding layer comprises a plurality of bonding parts corresponding to the micro devices.

7. The method of transferring micro devices as recited in claim 6 , wherein the bonding parts are formed on the micro devices, on the receiving substrate, or on both the micro devices and the receiving substrate.

8. The method of transferring micro devices as recited in claim 7 , wherein the bonding parts of the bonding layer are selectively formed on the micro devices.

9. The method of transferring micro devices as recited in claim 6 , wherein the buffer layer comprises a plurality of buffer parts corresponding to the micro devices .

10. The method of transferring micro devices as recited in claim 6 , wherein areas of orthographic projections of the bonding parts on the receiving substrate completely overlap and are smaller than areas of orthographic projections of the corresponding micro devices on the receiving substrate.

11. The method of transferring micro devices as recited in claim 6 , wherein each of the micro devices has two electrodes, and each of the bonding parts is formed into two parts separated from each other, and the two parts of the bonding parts correspond to the two electrodes of the micro device.

12. The method of transferring micro devices as recited in claim 4 , wherein the temperature of the carrier substrate differs from the temperature of the receiving substrate after the temperatures of the carrier substrate and the receiving substrate are changed.

13. The method of transferring micro devices as recited in claim 12 , wherein a material of the bonding layer is identical to a material of the buffer layer, a melting point temperature of the bonding layer is Tmr, the temperature of the carrier substrate is Tc, the temperature of the receiving substrate is Tr, and Tr<Tmr<Tc.

14. The method of transferring micro devices as recited in claim 12 , wherein a material of the bonding layer differs from a material of the buffer layer, a melting point temperature of the bonding layer is Tmr, a melting point temperature of the buffer layer is Tmc, the temperature of the carrier substrate is Tc, the temperature of the receiving substrate is Tr, and Tc>Tmc and Tr<Tmr.

15. The method of transferring micro devices as recited in claim 12 , wherein the buffer layer and the bonding layer are in different states after the temperatures of the carrier substrate and the receiving substrate are changed.

16. The method of transferring micro devices as recited in claim 1 , wherein the temperature of the carrier substrate is raised to a range from 50 degree Celsius to 200 degree Celsius.

17. The method of transferring micro devices as recited in claim 1 , wherein a maximum width of each of the micro devices is in a range from 3 μm to 100 μm.

18. The method of transferring micro devices as recited in claim 1 , wherein each of the micro devices is an inorganic light emitting diode.

19. The method of transferring micro devices as recited in claim 1 , wherein the carrier substrate is composed of an inorganic material, while the buffer layer is composed of an organic material, and hardness of the carrier substrate is greater than hardness of the buffer layer.

20. The method of transferring micro devices as recited in claim 19 , wherein a Young's modulus of the buffer layer is smaller than 10 GPa, while a Young's modulus of the carrier substrate is greater than 20 GPa.

21. The method of transferring micro devices as recited in claim 19 , wherein hardness of the micro devices is greater than the hardness of the buffer layer.

22. The method of transferring micro devices as recited in claim 21 , wherein a Young's modulus of the buffer layer is smaller than 10 GPa, while Young's modulus of the micro devices are greater than 20 GPa.

23. The method of transferring micro devices as recited in claim 1 , wherein surface roughness of the carrier substrate is smaller than 2.5 μm.

24. The method of transferring micro devices as recited in claim 1 , wherein the carrier substrate is disposed on a first supporting board and the receiving substrate is disposed on a second supporting board.

25. The method of transferring micro devices as recited in claim 24 , wherein raising the temperature of the carrier substrate comprises: raising the temperature of the carrier substrate by heating through the first supporting board or by heating through the second supporting board via a heat conduction mechanism.

26. The method of transferring micro devices as recited in claim 24 , wherein raising the temperature of the receiving substrate comprises: raising the temperature of the receiving substrate by heating the receiving substrate through the second supporting board.

27. The method of transferring micro devices as recited in claim 1 , wherein the temperatures of the carrier substrate and the receiving substrate are changed so at least a portion of the buffer layer is released from the carrier substrate and transferred onto the receiving substrate.

28. The method of transferring micro devices as recited in claim 1 , wherein at least a portion of the buffer layer is transferred to the receiving substrate with the at least a portion of the micro devices, and the at least a portion of the buffer layer is attached to the at least a portion of the micro devices.

29. A method of transferring micro devices, comprising: providing a carrier substrate, on which a buffer layer and a plurality of micro devices are disposed, the buffer layer being located between the carrier substrate and the micro devices, the buffer layer comprises a plurality of buffer parts corresponding to the micro devices, the buffer parts are separated from one another and expose a portion of the carrier substrate, the micro devices being separated from one another and positioned on the carrier substrate through the buffer layer; providing a bonding layer between the micro devices and a receiving substrate; making a receiving substrate contact the micro devices on the carrier substrate; after the micro devices contact the receiving substrate, reducing bonding force between at least a portion of the micro devices and the carrier substrate by melting the buffer layer through raising a temperature of the carrier substrate; and liquefying the bonding layer by raising a temperature of the receiving substrate such that adhesive force between the at least a portion of the micro devices and the bonding layer is greater than the bonding force between the at least a portion of the micro devices and the carrier substrate, so that the at least a portion of the micro devices are released from the carrier substrate and transferred onto the receiving substrate.

30. The method of transferring micro devices as recited in claim 29 , wherein the bonding layer is formed on the receiving substrate, or on both the micro devices and the receiving substrate.